Letters

In the July 2000 issue, Moshe Bar's article “Linux System
Calls” contained information that I would like to correct. I
suspect Moshe noticed by now that he was temporarily caught in a
pre-i386 time warp when he stated, “This routine sets up an IDT
(Interrupt Descriptor Table) with 256 entries, each 4 bytes long.
It should be noted that the IDT contains vectors...” This is more
a description of the pre-i386 IVT (interrupt vector table) than the
IA32's IDT.

The IA32 uses another level of indirection. In particular,
the IDT contains 8 byte descriptors which are either interrupt,
trap or task gates. I suspect Linux uses the first two varieties.
These gates contain the interrupt handler's 32-bit offset, some
attribute bits and a 16-bit selector which references a code
segment descriptor. In this case, that code segment descriptor is
in the GDT (global descriptor table). This descriptor also consists
of 8 bytes and vectors to the code segment containing the interrupt
handler. The entry point for the handler is derived from the 32-bit
offset lurking in the original IDT entry.

—Richard Sevenich rsevenic@netscape.net

Support for the WAP Article

I would like to express my support of more articles such as
the one on WAP in the July issue. Recently, I was working on a WAP
proof of concept for my organization. While I was motivated to move
on the project, I was having difficulties taking the relatively new
WAP standard and applying it in a straightforward manner to a
commercial-quality proof of concept my organization would support.
Mr. Mikal's article got to the meat of the issue and demonstrated
how to get productive in the WAP space, while leveraging the skill
sets that I, and other engineers here, already had. This one-page
article got the ball rolling on producing my organization's
wireless presence. In doing so, another organization has embraced
open-source and free software. It is articles like this, and the
knowledge sharing of the Linux community, that make magazines such
as Linux Journal welcome in my cubicle.

Thanks to Mr. Mikal and Linux Journal.

—Brad Wheat bradford.wheat@moai.com

iMac and Linux

When Linux began to grow in popularity, I jumped in, only to
be put down by fellow Linux users. I used Linux on a Macintosh. As
time went on and Linux distributions for the Mac grew, it became
obvious that Linux users would have to acknowledge the Mac. But,
rejection continued.

As a Mac user, I was aware of Linux before my PC pals. Apple
had MKLinux, “an Apple thing”, I was told. Today, SuSE, the #1
distribution of Linux, is available for the PPC. I'll be merciful
and not list all the others. After seeing the ads for PPC and
Yellow Dog, it's nice to see a couple of articles, unlike the one
degrading MKLinux in LJ a few months ago.
Thank you.

—Calvin Bowen ctbowen@mindspring.com

The Last Python Letters (We Swear!)

Two things on your Python supplement:

First, the uproar over the naked man. I honestly didn't
notice he was naked. After reading the Letters column, I went back
and looked; and sure enough, nothing but a bowtie. Considering how
much I've seen Laura Croft (and I've never seen or played whatever
video game she's in), it only seems fair that some computer
magazine would have a naked guy.

As for Guido's pet language (haha! ha! oh never mind...), I
must admit I think it's a bit lacking compared to Perl in one way.
A fixable way, mind you; this isn't a fatal flaw type of thing. The
problem is cpan—Python seems to be missing it. Perl has cpan;
pretty much all Perl modules can be found on cpan and installed
with the following steps:

perl Makefile.PL
make
make test
sudo make install

Now, I've been looking at Python for a specific problem: I
need to take data in a mySQL database and put it into a PostScript
printer. Python seems to be able to communicate with mySQL, and its
piddle module is both delightfully named and PostScript capable.

However, I still can't get mySQL connections to work, and the
piddle install file was bordering on useless (but I got it
working). I'll keep at it because I have to, but I think the Python
development community should attempt to recreate (and perhaps
improve) cpan. As a developer, I've found cpan to be one of the
best practical systems to enable code reuse. In fact, the C, C++
and pretty much all development communities would be wise to create
their own versions of cpan.

—Kevin Lyda kevin@suberic.net

I just got through reading all of the letters in the July
2000 issue from people complaining about the cover of the
supplement. Big deal! I own a computer store smack down in the
middle of the bible belt. I put all of my old magazines out front
for customers to look at while I am working on their computers, and
not one person has complained about the cover. I service people
from all walks of life, parents, teachers, clergy, children, etc.,
and no one has taken offense to the publication...in fact, it has
caused Windows-only kind of people to ask about Linux. Have even
had a couple of converts because of it.

Regardless of what anyone else says...keep up the good
work.

—Rodney Rees rodney@crass-enterprises.com

I read the July 2000 LJ Letters, which
was dedicated to reader responses to your Python supplement cover
in May. I could well remember that supplement which motivated me to
add Python to my language collection. It never occurred to me that
the cover picture was offensive.

Mind you, I am a university lecturer, and my pigeonhole is
transparent. This picture which annoyed so many in the Western
world went here, in an Asian, predominantly Buddhist country,
unnoticed!